import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Scanner;

public class GCRootsTest {
    public static void main(String[] args) {
        List<Object> numList = new ArrayList<>();

        Date birth = new Date();

        for (int i = 0; i < 100; i++) {
            numList.add(String.valueOf(i));
            try{
                Thread.sleep(10);
            }catch (InterruptedException e){
                e.printStackTrace();
            }
        }

        System.out.println("数据添加完毕，请操作：");
        new Scanner(System.in).next();
        numList=null;
        birth=null;


        System.out.println("numList,birth已置空，请操作：");
        new Scanner(System.in).next();

        System.out.println("结束！");
    }
}
